Valley Fever (coccidioidomycosis, or cocci) is caused by the soil-dwelling fungus, Coccidioides immitis. The tiny seeds, or spores, become wind-borne and are inhaled into the lungs, where the infection starts.

When soils containing the fungus are disturbed and dust is raised, spores may be inhaled with the dust. Dust disturbing activities include, the wind, construction, farming, among others.

Once inside the lung, the spore transforms itself into a larger, multicellular structure called a spherule. The spherule continues to grow and will eventually burst, releasing endospores which develop into new spherules, and then repeats the cycle (Figure 1).

Valley Fever is a sickness of degree. About 60 percent of the people who breathe the spores do not get sick at all. For some it may feel like a cold or flu. For those sick enough to go to the doctor, it can be serious, with pneumonia-like symptoms, requiring medications and bed rest.

Of all the people infected with Valley Fever, one or more out of 200 will develop the disseminated form, which is devastating, and can be fatal. These are the cases in which the disease spreads beyond the lungs through the bloodstream - typically to the skin, bones and the membranes surrounding the brain, causing meningitis.

The Endemic Area

Valley Fever derives its name from its discovery in the San Joaquin Valley of California, where it was also referred to as "San Joaquin Valley Fever", "desert rheumatism". Valley Fever is prevalent in the San Joaquin and Central Valleys of California, and in the hot, desert regions of southern Arizona (this includes the major metropolitan areas of Phoenix and Tucson), southern Nevada (including Las Vegas), southern Utah, southern New Mexico, western Texas (including El Paso), and Mexico (especially in the states of Sonora and Chihuahua). In addition, Coccidioides immitis is found in semiarid and arid soils in Central and South America

[And one of the latest victim is New York] Mets first baseman Ike Davis...Davis lives in Arizona in the offseason.

"Ike is not contagious, is not taking any medication for his condition and does not currently exhibit any of the outward symptoms associated with valley fever," the Mets said. "However, Ike has been instructed to avoid extreme fatigue. No additional tests or examinations are pending, but Ike will have a follow-up exam when the team returns to NYC in early April."

...Valley fever can be a serious problem – it caused Conor Jackson to miss all but the first 30 games of the 2009 season with the Arizona Diamondbacks. Greg Kraft had his promising golf career sidetracked after he contracted the disease during the 2002 Tucson Open.